Michael R. Krames

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Surface recombination is an important characteristic of an optoelectronic material. Although surface recombination is a limiting factor for very small devices it has not been studied intensively. We have investigated surface recombination velocity on the exposed surfaces of the AlGaN, InGaAs, and InGaAlP material systems by using absolute photoluminescence(More)
Twenty-two measures of color rendition have been reviewed and summarized. Each measure was computed for 401 illuminants comprising incandescent, light-emitting diode (LED) -phosphor, LED-mixed, fluorescent, high-intensity discharge (HID), and theoretical illuminants. A multidimensional scaling analysis (Matrix Stress = 0.0731, R(2) = 0.976) illustrates that(More)
The characteristics of blue InGaN multiple quantum well (MQW) Light Emitting Diodes (LEDs) with InGaN barriers are studied. The current-voltage (I-V) curve, Internal Quantum Efficiency (IQE), spontaneous rate are investigated. The simulation results show that the newly In0.15Ga0.85N /InGaN LED (Device 1) has reduced the forward voltage due to reduced energy(More)
We study the quantification of whiteness perception under illumination from various light sources. We discuss an existing metric for sources with high correlated color temperature (CCT), CIE whiteness, and propose a procedure to adapt it to sources of any CCT. We illustrate our approach by comparing the ability of different warm-white sources to render(More)
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